Demountable x-ray tube construction



Sept. 22, 1953 A. TAYLOR DEMOUNTABLE X-RAY TUBE CONSTRUCTION Filed June 5, 1952 iNVENTOR. 146F410)? Ey/or ATTORNEYS Patented Sept. 22, 1953 UNITED STATES PATENT OFFICE DEMOUNTABLE X B AY TUBE CONSTRUCTION Abraham Taylor, Cleveland, Ohio, assignor to Horizons Incorporated, Princeton, No .L, a corporation of New J erscy Application Jnne3, 1952, Serial l \lo. 291,478 In Great Britain January 12, 1949 5 claims.

This invention relates to de'mou'ntable X- ray tubes and, more particularly, to a rotating watercooled cylindrical anode assembly for such tubes. It is well known that the continuous output of an X-ray tube can be considerably increased if the heat generated at the focal spot ofthe elsetron beam striking the anode is eifectively dis sipated. The conventional procedure for dissipatin and distributing this heat over a rela-- tively large anode area is to rotate or oscillate the anode, and the removal of the heat thus dis= tributed 'OVer the large anode area is generally removed by auxiliary Cooling with circulating water or the like. or course, movement of the anode should be such as to maintain the focal spot of the electron beam at a fixed position with respect to the tube geometry, and this foca spot, comprising the sourceoi the X-ray beam, should be positioned as close as possible to the windows of the tube envelope in order to obtain a high value of emergent X-ray energy.

A characteristic construction of rotating anode assemblies for demountable X -ray tubes, that is, tubes provided with an auxiliary vacuum pumping'system, includes a hollow shaft mounted in the tube envelope, rotation of the anode being provided by rotation of the shaft and cooling of the anode being provided b circulation of water through the hollow shaft; The driving means for rotating the anode shaft is positioned ex= teriorly of the tube envelope, and such driving means has generally been positioned so close to the emergent X ray beam as to limit the useful area around the emergent beam' adjacent the tube window; As a result, the utility of such an X-ray tube is considerably restricted, particu= larly ii the tube is to be used with an fi ray diffraction camera which occupies a relatively large area adjacent the X-ray tube envelope.

The rotating water-cooled anode assembly of the present invention is characterized by its coin? p'actnes's-and arrangement of the anode driving mechanism. These features increase the acces= sibility, and hence the utility, of the -X=ray beam emerging from a window of a demountable-type tube positioned 'adjacentthe same side of the tube as the anode driving mechanism. The

anbd assfilbly Of my invention COYI'I'pTiS'S an anode sup orting frame adapted to be mounted in an opening in a sidewall of the X-ray tube envelope, the supporting frame being provided with an eccentrically 'posltloned'bea'ri'ng assem= tween the anode supporting frame and the anode driving sleeve. A cylindrical anode drum is mounted on the anode driving sleeve, one face of the drum being provided with an annular recess adapted to receive the driving sleeve, and conheating means are provided for securing the anode driving sleeve to the anode drum in substantially gas-tight relationship. An anode driving gear train is mounted on the anode supporting trains in engagement with the external end or the anode driving sleeve, and water supply and discharge lines are mounted communica tion with interior or the anode through the anode driving sleeve; The resulting structure comprises a water 'eooled cylindrical anode assembly characterized by unimpeded access to all tube "windows positioned peripherally thereof in the plane or emission of X-rays from the bylin drical drum surface.

These and other features of my invention will be more fully understood by reference to the accompanying drawing in which Fig. l is a cross-sectional view of the anode assembly of the invention mounted in an X-ra'y tube envelope, the section being taken along line Fig; 2 is an exterior plan view of the anode assembly shown in Fig. l; and

Fig. 3 is a section takenoalong line Figi 1i The anode assembly, particularly as shown in Figs. 1 and '2, is mounted in one end portion of an envelope 5 of a conventional demountable type X-ray tube. The anode assembly includes s-e in an anode supporting frame 6 having a peripheral flange portion 1 and an inwardl recessed body portion 8; The flange portion 1 is shaped to con form to the outline of the tube opening 9 which receives the anode assembly, the joint between the flange I and the edge of the tube opening ll beingcornpleted by anyappropriate sealing ma terial such as a soft gasket It. inasmuch as the anode supporting frame and its associated strum ture functions as a cover plate for the tube on velope opening 9, the sup orting frame can be held tightly against the tube opening by the maintenance of a vacuum within the tube. It will be seen. accordingly, that a gas-tight seal may be provided betweenthe envelope 5. of the X-ray tube and the main body portion 8 ofthe anode supporting frame withoutany extraneous clamping structure. 7

The body portion of the anode Supporting frame, as clearly shown in Fig. 1; is provided eccentrically thereof with a bearing assembly projecting in the direction of the interior of the tube. The bearing assembly is composed of an inwardly projecting annular body portion H provided internally adjacent its extremities with vacuum seal retaining rings I2 and i2. Within the space defined by the annular body portion H and the two retaining rings 52 and i2 there is mounted a suitable vacuum seal device such as the greased chevron rings I3 which are urged radially towards their axis by compression springs Id. The vacuum seal rings I3 are thus urged against the outer surface of an axially positioned anode supporting sleeve [5 mounted within the annular body portion H of the anode bearing assembly. The supporting sleeve [5 is providedwith a radially outwardly projecting flange l6 threaded onto its inner extremity and is provided adjacent its outer extremity with a similarly disposed but integrally formed flange ll. The flanges it and Il thus embrace the inwardly'projecting retaining rings l2 and I2 on the body portion H of the bearing assembly, and ball bearings it are mounted therebetween so that the anode sleeve it may be rotated freely within the body portion of the anode bearing assembly. Accordingly, the rotatable sleeve is is adapted to carry an anode drum so that the drum may be rotated by driving the sleeve 55.

The anode drum l9 comprises a cylindrical shell 26 one peripheral edge of which is formed integrally with or soldered to a face plate 2!. The other peripheral edge of the cylindrical anode shell has mounted thereon, preferably by soldering or the like, a faceplate 22 provided with an inwardly recessed portion or well 23. The base of the recessed portion 23 is closed by a relatively thick body portion 24' which is provided axially thereof with an up-struck sleeve portion 2 5 so proportioned as to extend Within and through out the full length of the bearing sleeve 55. The outer end of the anode drum sleeve 25 is provided with a threaded portion 2'5 onto which a threaded drive cap assembly 26 is screwed. By

tightening the drive cap assembly on the sleeve 25, the body portion 24 of the recessed anode drum face is forced against the innermost bearing flange It so as to compress a gasket 28 of rubber or the like therebetween and thus form a gas-tight seal.

rotation of these parts as they are being brought together, further enhances the emcacy and durability of the seal.

It will be clearly apparent, accordingly, that maintenance of a vacuum within the tube envelope 5 is insured by the gasket 28 which seals the joint between the recessed face of the anode drum and the anode bearing sleeve I5, by the vacuum seal I3 provided between the anode sleeve !5 and the body portion H of the bearing as-' sembly of the anode supporting frame, and by the sealed engagement of the flange l of the anode supporting frame with the tube envelope 5. Thus, a suitably high vacuum may be maintained by an active vacuum pump system associated with the tube envelop-e while rotating the anode drum [9 by driving the rotatable anode sleeve E5.

The driving mechanism for the anode sleeve comprises a gear train engaging gear teeth 29 provided on the drive cap 26 secured to the end of the anode drum sleeve 25. The frictional contact between the drive cap and the outer flange ll of the anode driving sleeve it provides a positive driving connection between the cap and the Corrugation of these parts which engage the gasket 28, and the absence of relative.

a 4 sleeve. The gear train may comprise any appropriate number and combination of sizes of gears positioned within the recessed body portion 8 of the anode supporting frame, and the gear train is advantageously, though not necessarily, driven in such direction as to turn the drive cap 26 in the direction of tightening its grip on the sleeve threads 2?. In the embodiment of the invention shown in the drawing, the gear train comprises two gears 3t and 35 mounted on bosses 32 and 33, respectively, struck up from the body portion 8 of the anode supporting frame. The driving gear 3! is, in turn, connected to the drive pulley 34 which is driven by a conventional belt 35, or the like. It can be seen clearly in Figs. 1 and 2 that the position of the drive pulley 34, which is the only part of the anode assembly that extends outwardly beyond the face of the tube envelope in the modification shown in the drawings, is sufficiently removed from the adjacent tube window 36 as to leave completely accessible a large area surrounding the window. If desired, a portion of the anode supporting frame flange 1 and a corresponding portion of the tube envelope 5 may be recessed to accommodate the drive belt 35 and thus permit the drive pulley to be mounted in the supporting frame flush with or inside the plane of the tube envelope. In this latter modification of the anode assembly of my invention, no part of the assembly will extend beyond the contour of the tube envelope itself. In all modifications of the anode assembly of the invention, the assembly is characterized by an anode supporting frame having a raised peripheral flange adapted to engage the tube wall opening and with all elements of the anode assembly, with the possible exception of the drive pulley 34, positioned inwardly of the tube with respect to the plane of said peripheral flange.

Although the water-cooling connections for the anode drum are mounted axially of the drum assembly, the positioning of the drive pulley 35 away from the drum axis leaves available for the water connection a recessed portion of the complete assembly. Accordingly, water supply and discharge lines 3! and 38, respectively, are brought into the axis of the drum within the recess space provided by the plane of the anode supporting frame flange l and the outermost surface of the drive cap 2'5. The water connections to the interior of the drum are provided by a stationary union composed of a cylindrical sleeve 39 having a tube portion id mounted therewithin. The water supply line iii communicates with the outer extremity of thesleeve 39 and the water in the body p-ortion'2 l of the recessed anode drum face. A dish-shaped baiile 22 provided with an axial opening Mfand mounted securely on the inner face of the body portion 24 of the recessed anode drum face, provides a partition within the anode drum through which cooling water may flow. Thus, cooling water from the supply line 3! flows inwardly through the tube it, thence between the face of the bafile plate 42 and the inner surface of the drum face 2! of the anode, through the outer chamber of the anode drum where it passes in direct contact with the cylindrical shell 26 of the anode drum. The cooling water thence flows into the inner chamber of the drum and through a plurality ofradial openings it drilled or otherwise'forme'd in the body portion 24 of the recessed anode drum face, six such radial assessedopenings being provided in the modification shown in Figs; 2 and 3. The Water issuing from the inner ends of the openings 44 passes into the cylindrical sleeve 39 of the water coupling and thence through the discharge line '38, A packing gland 45 positioned within the drive can assembly 26 maintains a water seal between the anode drivingsleeve and the stationary water supply union; in operation of the apparatus of my invention, the pulley 34 is driven so as to drive the gear train and theanode drivi g sleeve [5 and thus rotate the anode drum I9, A stream of high velocity electrons from a conventional incomescent cathode 46, focused by the externauy adjustable shield 41, impinges on the cylindrical anode shell at of the drum, and the resultin X=r y beam 48 leaves the drum surface at a low angle of incidence (a proximately 5) and passes through the tube windows. The absence of any obstruction beyond the plane or the tube envelope 5 adjacent that portion ofthe anode sup porting frame nearest the tube window 35 makes this window as completely useful as all other windows which may be provided peripherally about the tube envelope. H 0f course, the characteristics of the emergent X-ray beam may be modified by interchanging anode drums having cylindrical shells 20 formed of metals which vvill provide the desired X-ray beam characteristics. Thus, al though a conventional copper anode surface may beprovided by forming the shell 20 of copper or of a copper plated basemetal, other metals may be used in lieu of copper. If desired, a variety of X-ray beam characteristics may be obtained by plating, or otherwise positioning, on the surface of the drum 20 a plurality of segments composed of a variety of other metals. By limiting rotation of the anode drum by an angular oscillation equal to the angular extent of each such segment, the tube may be operated to supply at will the characteristic X-ray radiation of the metal of such segment while nevertheless taking advantage of the other virtues of my novel anode assembly structure. Accordingly, the term rotating as used herein and in the claims, includes continuous uninterrupted rotation in a single direction as well as oscillatory rotation of either a multiple or a fraction of a complete revolution.

It will be appreciated that the rotating anode assembly of my invention is relatively simple in construction and that it is readily amenable to disassembly and removal from the tube envelope. The compactness of the anode assembly makes it a particularly valuable adjunct to a demountable X-ray tube, and its substantially flush outer contour enhances the utility of such 1 a tube embodying this anode assembly.

I claim: 1. A rotating water-cooled cylindrical anode assembly for demountable X-ray tubes characterized by unimpeded access to all tube windows positioned peripherally thereof in the plane of emission of X-rays from the cylindrical wall surface of the drum and comprising an anode supporting frame adapted to be mounted in an opening in a side wall of an X-ray tube envelope, the supporting frame being provided with an eccentrically positioned bearing assembly projecting in the direction of the interior of the tube, an anode driving sleeve positioned within said bearing assembly, sealing means providing'a substantially gas-tight seal between the anode supporting frame and the, anode driving sleeve, a cylindrical anode drum mounted for rotation in a plane par- E1151 lib the P181113 Of the afiOd supporting frame, one race of the drum being provided with an annular recess adapted to receive the anode driving sleeve,- connecting means for securing the anode driving sleeve to the annular recess in the anode drum in substantially gas-tight relation'- ship, an anode driving gear train mounted on the anode supporting frame in en agement with the 'alibd driving sleeve, and water supply and discharge lilies communicating With the interior of the anode drum through said anode driving sleeve.

'2. A rotating water' -cooled cylindrical anode assembly for demountable X raytubes characterized by unimpeded access to all tube windows positioned peripherally thereof in the plane of emissionof X ra s from the cylindrical wall sur face or the drum andcemprising an anode sup porting frame having a main body portion and a raised peri heral flange adapted to be mounted in an opening in a side wall of an X-ray tube envelope, the supporting frame being provided with an eccentrically positioned bearing assembly projecting in thedirectlon of the interior of the tube, an anode driving sleeve positioned within saidbearing assembly, sealing means providing a substantially gas-=tight seal between the anode supporting frame and the anode driving sleeve, a

cylindrical anode drum one. face of which is provided with an annular recess adapted to receive the anode driving sleeve, connecting means for securing the anode driving sleeve to the an, nuiar recess in the anode drum in substantially gas-tight relationship, an anode driving gear train mounted on the anode supporting frame in engagement with the anode driving sleeve, and water supply and discharge lines communicating with the interior of the anode drum through said anode driving sleeve, all previously recited elements of the assembly being positioned inwardly of the tube with respect to the plane of the peripheral flange of the anode supporting frame.

3. A rotating water-cooled cylindrical anode assembly for demountable X-ray tubes characterized by unimpeded access to all tube windows positioned peripherally thereof in the plane of emission of X-rays from the cylindrical wall surface of the drum and comprising an anode supporting frame adapted to be mounted in an opening in a side wall of an X-ray tube envelope, the supporting frame being provided with an inwardly recessed main body portion in which there is mounted an eccentrically positioned bearing assembly projecting in the direction of the interior of the tube, an anode driving sleeve positioned within said bearing assembly, sealing means providing a substantially gas-tight seal between the anode supporting frame and the anode driving sleeve, a cylindrical anode drum one face of which is provided with an annular recess adapted to receive the anode driving sleeve, connecting means for securing the anode driving sleeve to the annular recess in the anode drum in substantially gas-tight relationship, an anode driving gear train mounted on the anode supporting frame in engagement with the anode driving sleeve, and water supply and discharge lines communicating with the interior of the anode drum through said anode driving sleeve.

4. A rotating water-cooled cylindrical anode assembly for demountable X-ray tubes characterized by unimpeded access to all tube windows positioned peripherally thereof in the plane of emission of X-rays from the cylindrical wall surface of the drum and comprising an anode supporting frame adapted to be mounted in an opening in a side wall of an X-ray tube envelope, the supporting frame being provided with an inwardly recessed main body portion in which there is mounted an eccentrically positioned bearing assembly projecting in the direction of the interior of the tube, an anode driving sleeve positioned within said bearing assembly, sealing means providing a substantially gas-tight seal between the anode supporting frame and the anode driving sleeve, a cylindrical anode drum one face of which is provided with an annular recess adapted to receive the anode driving sleeve, connecting means for securing the anode driving sleeve to the annular recess in the anode drum in substantially gas-tight relationship, an anode driving gear train mounted on the anode sup porting frame in engagement with the anode driving sleeve and positioned within the recessed body portion of said supporting frame, and water supply and discharge lines communicating with the interior of the anode drum through said anode driving sleeve.

5. A rotating water-cooled cylindrical anode assembly for demountable X-ray tubes characterized by unimpeded access to all tube windows positioned peripherally thereof in the plane of emission of X-rays from the cylindrical wall surface of the drum and comprising an anode supporting frame adapted to be mounted in an opening in a side wall of an X-ray tube envelope, the supporting frame being provided with an inwardly recessed main body portion in which there is mounted an eccentrically positioned bearing assembly projecting in the direction of the interior of the tube, an anode driving sleeve positioned within said bearing assembly, sealing means providing a substantially gas-tight seal between the anode supporting frame and the anode driving sleeve, a cylindrical anode drum one face of which is provided with an annular recess adapted to receive the anode driving sleeve, connecting means for securing the anode driving sleeve to the annular recess in the anode drum in substantially gas-tight relationship, an anode driving gear train mounted on-the anode supporting frame in engagement with the anode drivin sleeve and positioned within the recessed body portion of said supporting frame, and water supply and discharge lines communicating with the interior of the anode drum through said anode driving sleeve, the water supply and discharge lines being connected to the anode driving sleeve within the recess provided by the recessed body portion of the anode supporting frame.

ABRAHAM TAYLOR.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,209,963 Du Mond Aug. 6, 1940 2,213,112 'Iimmons Aug. 27, 1940 2,468,942 Costerkamp et al. May 3, 1949 2,488,200 Juhlin et al. Nov. 15, 1949 2,535,708 Vlach Dec. 26, 1950 

